Though hers is the central character in the story, Grace Kelly does not sing a solo. Indeed, but for accompanying Bing Crosby on "True Love" and drunkenly shouting, "Sensational," she wouldn't sing at all (rare for a musical).
The song True Love, written by Cole Porter especially for the movie, was a million seller and both Grace Kelly and Bing Crosby were awarded platinum records for the song. This is the only platinum record ever given to sitting royalty as Grace Kelly had become Princess Grace by the time it was awarded.
Grace Kelly, recently engaged to Prince Rainier of Monaco, wore her actual engagement ring for her character's engagement ring. The engagement ring is a 10.5-carat, emerald-cut, diamond flanked by two baguettes.
High Society (1955), a "Bowery Boys" comedy that had been released the previous year, was mistakenly nominated for an Academy Award for "Best Writing - Original Story" in 1957, because the Academy confused it with this film, which was still in wide release when the 1957 nominations were announced. When the mistake was discovered, Edward Bernds and Elwood Ullman, the two screenwriters of the "Bowery Boys" film, graciously declined the nomination.
It is believed that Frank Sinatra's brand new car, a 1956 Continental Mark II (now a very rare item as only 4,000 were ever made and sold) was used in some brief shots in the film released July, 1956. Actor Louis Calhern is seen exiting the car while being greeted by Grace Kelly. Records show the car being delivered to Sinatra December, 1955 so it seems a good bet that it is indeed the one in the film.
At one point Tracy's mother (Margalo Gillmore) mentions that Dexter (Bing Crosby) and Tracy (Grace Kelly) grew up together. This is interesting and highly unlikely, as Bing is 26 years older than Grace. However, the phrase "grew up together" means more that they gained experience due to this being their first marriage. In this context, one can surmise that they went into this marriage lacking in maturity.